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R. Silva" Cc: Erick Archer , Mathieu Desnoyers , Mark Rutland , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH v2] eventfs: Use kcalloc() instead of kzalloc() Date: Mon, 15 Jan 2024 19:16:58 +0100 Message-Id: <20240115181658.4562-1-erick.archer@gmx.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Provags-ID: V03:K1:0g1HcZkBjgXbdwH65/z58cKfoG4eUSOlTy25Nx06xre/KJiWz4m SkPbpl8fGlc4UQ18ujM97F85F9hLPqeA2rmTQVOdDPLmgvPVXEW1+wNQghH23fXjERqJgn8 5+0mZwbu/iR2h9imQ5RadyEP5N7gCOamNmJflA7sQTdjSJNCULkcOre6u+k6EUGN0ctsMvF NGLVPUEJAccHJyXBkloCQ== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:VxCX+FbTuiU=;wa/Qu/GPbrz8jMjfxFIdVgsNWZl PxHOAK6x+m+be9+s4+J1CKTt3/gvAAtZusqrYKVLAwKKm1Tqd5wk/7jm6HAVRHQYGjrCCZp+j fo+CeafPcQ+uQFCbuZHJbHxuESYX9IKw/OBOY4jwarZBdSFcAH7mlpmlaCAExWqTyFhHeBpYv NYE9lRDSrAHDajnxZNJOaP2BiuN8YCZWjeAKxDS8H5wWLz7ueE6Z9aqnHOzXZm3pex2gpnWDh hD2oCNXd9WIDMrkppIbG7ut6y4u5X1dWZWXAfRxnbCDG7onwZT12SCWJvY5cw6OZ6bTsiRs5P Qr9p0StE0I4MtJOPvHnYsK/1XE/vvAF32pOGssQMIogxDV187555ry2EWoYHTIa8BOtTCClTe /aM/bUfbUUnJUBTOq1+U6lgRXW6f3Hd9ojET5h6ht7VXcpQ7/Tn6XaPPa97qy/fJ96+CUWhUU r3DsZISn79iXPvjLv5vHrD8T3SAcikgdN72hZN7pEfmFjxjY1JcgQiacCFcrmkJazQcoCmrcH JsenuGsEKgI0KZ+kbEKsOqo6prl6FW8inPOCi3QokB5WYGGuFIzug9v9GQi9l/sv5HBjJHUuf /BWcZsMlgOkKk1WOIlqPuoMoU2cXPraaRnoOIh8Vw4k77UdYNPaKB3TyOug6BBKYu3trhhYDE 4p/RcrUGXC+2zSa9h2rY0Cw17ArTOUkFy/Xo2ByPIv+lQhojXLtoDFkJtJxDe6tQrpmYi5W1v 5AMtnvkw7wTBC49m9mlX/5ox8LT0pHwIItNprhmg+IkaB/VLDtjWSF3MpPyaeLSesf3BCDCxU 8ZhdlqjjmJBrx7JkBPRVq6mR8/5bBndmifJyNZ8l2Qy5jIwBCTPOEJ+wQSiBAxBeg13rBgBYa FjZ4mULJPtQrUHS5KldLCD74/9bESBW+VCLqiq0nt2HlwbRwRg/Ikj1Mi+fr4UPzDjH+yi8Gr 7p/I7Q== As noted in the "Deprecated Interfaces, Language Features, Attributes, and Conventions" documentation [1], size calculations (especially multiplication) should not be performed in memory allocator (or similar) function arguments due to the risk of them overflowing. This could lead to values wrapping around and a smaller allocation being made than the caller was expecting. Using those allocations could lead to linear overflows of heap memory and other misbehaviors. So, use the purpose specific kcalloc() function instead of the argument size * count in the kzalloc() function. [1] https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments Link: https://github.com/KSPP/linux/issues/162 Signed-off-by: Erick Archer Reviewed-by: Gustavo A. R. Silva --- Changes in v2: - Update the commit message to better explain the changes (Mark Rutland) Previous versions: v1: https://lore.kernel.org/linux-hardening/20240114105340.5746-1-erick.archer@gmx.com/ --- fs/tracefs/event_inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) -- 2.25.1 diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index fdff53d5a1f8..f8196289692c 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -93,7 +93,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry, /* Preallocate the children mode array if necessary */ if (!(dentry->d_inode->i_mode & S_IFDIR)) { if (!ei->entry_attrs) { - ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries, + ei->entry_attrs = kcalloc(ei->nr_entries, sizeof(*ei->entry_attrs), GFP_NOFS); if (!ei->entry_attrs) { ret = -ENOMEM; @@ -874,7 +874,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode } if (size) { - ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL); + ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL); if (!ei->d_children) { kfree_const(ei->name); kfree(ei); @@ -941,7 +941,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry goto fail; if (size) { - ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL); + ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL); if (!ei->d_children) goto fail; }